Need
Need, Demand and Desire
Around 1958, Lacan develops an important distinction between three terms:
Need and Instinct
In the context of this distinction, "need" comes close to what Freud referred to as "instinct" (Instinkt); that is, a purely biological concept opposed to the realm of the drive (Trieb).
Need and Demand
Lacan bases this distinction on the fact that in order to satisfy his needs the infant must articulate them in language; in other words, the infant must articulate his needs in a "demand".
However, in doing so, something else is introduced which causes a split between need and demand; this is the fact that every demand is not only an articulation of need but also an (unconditional) demand for love.
Now, althought the other to whom the demand is addressed (in the first instance, the mother) can and may supply the object which satisfies the infant's need, she is never in a position to answer the demand for love unconditionally, because she too is divided.
The result of this split between need and demand is an insatiable leftover, which is desire itself.
Need and Desire
Need is thus an intermittent tension which arises for purely organic reasons and which is discharged entirely by the specific action corresponding to the particular need in question.
Desire, on the other hand, is a constand force which can never be satisfied, the constant 'pressure' which underlies the drives.
